Utilization of 2,6-diaminopurine by Salmonella typhimurium
Utilization of 2,6-diaminopurine by Salmonella typhimurium
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鼠伤寒沙门氏菌对 2,6-二氨基嘌呤的利用
DOI：
10.1128/jb.143.2.864-871.1980
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发表时间：
1980
影响因子：
3.2
通讯作者：
J. Gots
中科院分区：
文献类型：
--
作者：
B. Garber;J. Gots
研究了鼠伤寒沙门氏菌利用2，6-二氨基嘌呤（DAP）作为外源性嘌呤来源的途径。在能够使用DAP作为嘌呤源的菌株中，缺乏嘌呤核苷磷酸化酶或腺苷脱氨酶活性的突变衍生物失去了这样做的能力。DAP利用的暗示途径是通过嘌呤核苷磷酸化酶将其转化为DAP核糖核苷，然后通过腺苷脱氨酶脱氨基为鸟苷。鸟苷然后可以进入已建立的嘌呤补救途径。在确定这一途径的过程中，嘌呤营养缺陷型能够利用DAP作为唯一的嘌呤源进行分离和部分表征。这些突变体分为几类，包括（i）仅需要外源鸟嘌呤核苷酸来源的菌株（例如，guaA和guaB菌株）;（ii）具有purF遗传损伤的菌株（即，α-5-磷酸核糖基1-焦磷酸酰胺转移酶活性缺陷）;和（iii）具有组成型水平嘌呤核苷磷酸化酶的菌株。为了在作为嘌呤核苷酸的唯一来源的DAP上有效生长，在肌苷5 '-单磷酸从头合成中被阻断的嘌呤营养缺陷型中进行选择，容易产生在其脱氧核糖核苷分解代谢酶的调节中有缺陷的突变体（例如，deoR突变体）。
The pathway for the utilization of 2,6-diaminopurine (DAP) as an exogenous purine source in Salmonella typhimurium was examined. In strains able to use DAP as a purine source, mutant derivatives lacking either purine nucleoside phosphorylase or adenosine deaminase activity lost the ability to do so. The implied pathway of DAP utilization was via its conversion to DAP ribonucleoside by purine nucleoside phosphorylase, followed by deamination to guanosine by adenosine deaminase. Guanosine can then enter the established purine salvage pathways. In the course of defining this pathway, purine auxotrophs able to utilize DAP as sole purine source were isolated and partially characterized. These mutants fell into several classes, including (i) strains that only required an exogenous source of guanine nucleotides (e.g., guaA and guaB strains); (ii) strains that had a purF genetic lesion (i.e., were defective in alpha-5-phosphoribosyl 1-pyrophosphate amidotransferase activity); and (iii) strains that had constitutive levels of purine nucleoside phosphorylase. Selection among purine auxotrophs blocked in the de novo synthesis of inosine 5'-monophosphate, for efficient growth on DAP as sole source of purine nucleotides, readily yielded mutants which were defective in the regulation of their deoxyribonucleoside-catabolizing enzymes (e.g., deoR mutants).